In fog, a pilot vessel is required to sound one long blast followed by two short blasts on its whistle at intervals of not more than two minutes. The long blast indicates the vessel's presence, while the two short blasts signal its role as a pilot vessel. This sound signal helps other vessels in the vicinity to identify the pilot vessel's location and intentions in reduced visibility conditions.
A Fog Horn.
A vessel that sounds the same fog signal whether underway or at anchor is a sailing vessel. According to the International Regulations for Preventing Collisions at Sea (COLREGs), a sailing vessel under sail alone is required to sound one prolonged blast followed by two short blasts. This signal is used to indicate its presence and position in reduced visibility conditions, regardless of its status.
If you hear the fog signal of another boat, first determine the direction of the sound to assess the other vessel's location. Maintain a proper lookout and reduce your speed to avoid collisions. Use your radar and navigation tools to track nearby vessels, and be prepared to take evasive action if necessary. Additionally, sound your own fog signal to alert others to your presence.
A power-driven vessel under way sounds one prolonged blast not less than every two minutes. However if it is less than 12meters in length it is not required to give any signal.
Rule 35 part c of the International Regulations for Preventing Collisions at Sea (72 COLREGS) states that when in restricted visibility (i.e. fog) a sailing vessel is required to sound one prolonged blast followed by two short blasts on the vessel's whistle, at intervals of not more than two minutes. Please refer to the link below.
When a powerboat is underway in fog, it should sound its horn every two minutes with one prolonged blast lasting about four to six seconds. This signal alerts other vessels to its presence, as visibility is limited in foggy conditions. Additionally, if the powerboat is approaching another vessel, it may also sound short blasts to indicate its intentions.
The sound signal that you should hear when a power boat is in the fog is one prolonged blast at intervals of no more than 2 minutes.
I am a power-driven vessel underway. Sound signals let other boaters know where you are located during periods of restricted visibility, such as extreme fog. If you hear the fog signal of a vessel you cannot see, slow to a minimum speed until you are sure there is not a risk of collision. One prolonged blast at intervals of not more than two minutes is the signal used by power-driven vessels when underway.
I am a power-driven vessel underway. Sound signals let other boaters know where you are located during periods of restricted visibility, such as extreme fog. If you hear the fog signal of a vessel you cannot see, slow to a minimum speed until you are sure there is not a risk of collision. One prolonged blast at intervals of not more than two minutes is the signal used by power-driven vessels when underway.
One prolonged blast followed two short blasts, every two minutes, not to exceed two minutes. Rule 35-Sound Signals in restricted visibility.
Rules of the RoadRule 35Sound Signals in Restricted Visibility(C) A vessel not under command, a vessel restricted in her ability to maneuver, a vessel constrained by her draft, a sailing vessel, a vessel engaged in fishing, and a vessel engaged in towing or pushing another vessel shall..........sound at intervals of not more than two minutes, three blast in succession, namely one prolonged followed by two short blasts.
A sailing vessel making way should signal, long-short-short every two minutes in fog.